1. Field of Invention
The present invention relates to electrical connectors. More specifically, the present invention relates to a socket for an electrical component.
2. Description of Reported Developments
Electrical components, such as integrated circuit (IC) chips, must be secured to a substrate. One example of an interconnection system for securing such pin grid array (PGA) components to a substrate is a zero insertion force (ZIF) system. In ZIF systems, pins of the PGA component enter an interconnect housing without engaging contacts of the interconnect mounted to the substrate. Only after the PGA component seats on the interconnect housing are the contacts and pins engaged.
One method of engaging the contacts and PGA pins involves moving the PGA pins laterally and into engagement with the contacts. An actuating lever and a cam surface drive an interposer assembly laterally to propel the PGA pins. The interposer assembly moves the PGA pins towards, and into connection with, the contacts.
The housing used with such ZIF interconnects encounters loading during, and after, lever actuation. The forces required to deflect the contacts in order to receive the PGA pins determines the amount of loading on the housing. The greater number of contacts increases the peak, or maximum force required to mate the contacts and PGA pins. It is estimated that an interconnect with 500 contacts requires approximately twenty (20) pounds of force to mate the contacts and PGA pins successfully.
Technological advances have increased the pin count and contact density of PGA components and have miniaturized computer components (requiring reduced profile sizes). While the improved speed may satisfy consumers, these technological advances burden conventional ZIF sockets. Often, a design that compensates for one of the above technological advances is mutually exclusive to a design that compensates for another technological advance.
In one example of a modification, a designer may increase the number of holes in the socket and decrease the pitch between the holes to account for increased pin density and the pin count. However, this reduces the strength of the socket.
In another example of a modification, a designer may shorten the contact to account for reduced profile size. A shorter contact exhibits greater stiffness, thus increasing the required insertion force to mate with the PGA pins.
These two design objectives impose conflicting requirements, since a stiffer contact requires more actuation force on the lever. A larger actuation force increases the loading on the socket. But the reduced strength of the socket (due to the increased hole count and decreases pitch) renders the socket less likely to withstand the increased loading.
The increased contact density has also taxed the capabilities of conventional contact forming methods. The typical method of forming opposed dual beam contacts is to stamp the contact from a sheet of material. However, the width of the sheet material required to form a single contact with conventional techniques will exceed the pitch requirements imposed by these technological advances.